Concrete drum drive support

ABSTRACT

A truck mounted inclined axis concrete mixer drum is mounted at its lower, closed end on a drive shaft by means of a half spherical bearing positioned closely adjacent the point of support of the drive shaft to minimize overhang of the drive shaft as well as to compensate for misalignments. A floating holding arrangement rearwardly of the half spherical bearing support assists gravity in holding the drum onto the bearing.

United States Patent [191 Mihulowicz 1 I Dec. 3, 1974 CONCRETE DRUM DRIVE SUPPORT [75] Inventor: George Mihulowicz, Greendale, Wis.

[73] Assignee: Rexnord Inc., Milwaukee, Wis.

[22] Filed: July 17, 1972 211 Appl. No.: 272,513

[52] US. Cl 259/177 R [51] Int. Cl. 1328c 5/18 [58] Field of Search 259/168, 175, 176, 177 R,

[56] References Cited UNITED STATES PATENTS 2,563,336 8/1951 Jaeger 259/177 2,624,557 l/l953 Gerst 259/168 ODea 259/177 Buelow 259/177 A Primary Examiner-Robert W. Jenkins Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A truck mounted inclined axis concrete mixer drum is mounted at its lower, closed end on a drive shaft by means of a half spherical bearing positioned closely adjacent the point of support of the drive shaft to minimize overhang of the drive shaft as well as to compensate for misalignments. A floating holding arrangement rearwardly of the half spherical bearing support assists gravity in holding the drum onto the bearing,

5 Claims, 4 Drawing Figures PATENTEBDE 3.85L862 sum 10; 2

CONCRETE DRUM DRIVE SUPPORT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in the art of supporting and driving the forward end of an inclined axis concrete mixing drum.

2. Prior Art It is known in the prior art to mount concrete mixer drums on trucks with the rear end of the drum inclined upwardly and with the drive for the drum at the front end of the drum through suitable gearing. It is also known to mount the front end of the drum to compensate for misalignment, due to limberness of the truck mounting the drum, by supporting the drum on a spherical bearing and driving the drum through a coupling which will compensate for such misalignment. In typical prior art of this type, for example as shown in the expired patents to Jaeger US. Pat. No. 2,563,336 or Gerst US. Pat. No. 2,624,557 there is a significant length of the support and drive shaft which extends beyond the rearmost bearing supporting the drum shaft. This results in a cantilever effect of the support and drive shaft with the weight of the drum creating problems in bearing wear and the like due to shaft deflections of the cantilever mounted shaft. The'prior art drums, even though they were only designed to mix 3 or 4 cubic yards of concrete, were generally commercially unsucessful due to this significant problem. Today concrete mixer drums are designed to mix up to .and over cubic yards of concrete and the loading problems on the support shaft have significantly increased.

SUMMARY OF THE INVENTION This invention solves the problems of the prior art by mounting the drum on a half spherical bearing carried by the support shaft adjacent the main support bearing. By virtue of using only a half spherical bearing instead of a full spherical bearing, the main support bearing can be moved closer to the point of load on the shaft; thus, minimizing the cantilever support distance or the shaft overhang. While the weight of the inclined drum and gravity are normally sufficient to hold the drum onto the support bearing, an additional floating means utilizing radial floating elements and shims or Belleville washers between the end of the support shaft and drum is utilized to furnish additional holding force.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevation view of a truck mounted mixer drum incorporating the drive and mounting arrangement of this invention.

FIG. 2 is a side elevation with portions broken away of the drive and housing therefor.

FIG. 3 is a rear elevation view with portions broken away of the drive and housing of FIG. 2.

FIG. 4 is an enlarged side sectional view showing the drive and mounting arrangement of this invention in detail.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT As shown in FIG. 1, a truck 10 mounts a mixer drum 12 which is inclined forwardly and downwardly and supported by the conventional rear drum supports 14 as in US. PAT. NO. 3,073,580. The drumm has a front end support and drive 16. A hydraulic pump 18 mounted on the front of the truck and driven by the engine provides hydraulic fluid under pressure through lines not shown to activate a hydraulic motor 20 connected to a gear reduction unit 22; The gear reduction unit is encased within housing 24 which in turn is mounted on support column 26 attached to the truck body. A drive shaft 28 of the gear reduction unit drives and also furnishes the support for the front end of the mixer drum 12.

Referring now to FIG. 4, a final drive gear 30 is attached to drive and support shaft 28 by spline 32. The inclined shaft 28 is rotatably supported on gear casing 24 by tapered roller bearings including a lower end bearing 34 and a main bearing 36 cooperating in housing bosses 38 and 42 respectively of the gear case. A holding nut 40 holds the bearing 34 onto the lower end of the shaft while the main bearing 36 abuts against a drive spline 44 on the shaft 28.

A drive coupling for driving the drum 12 includes an external gear coupling member 45 having an internal spline which fits spline 44. Outwardly of the spline is a spacer 48 and a half spherical bearing 50 mounted on the shaft 28.

The mixer drum 12 carries a drum head hub 52 having a cover 54 and an internal gear coupling 56 having teeth which mesh with external gear coupling 46 and shaped to allow a small amount of misalignment of the drum relative to the support shaft 28. Screws 58 secure the internal gear coupling 56 to the drum 12. These screws extend into a drum head mounting ring 60 welded to the drum 12 which mounting ring has flanges for holding the drum head hub 52.

The drum head 52 carries the outer spherical bearing 62 which has a part spherical surface cooperating with the part spherical surface of bearing 50. As the mixer drum is misaligned due to flexibility or limberness of the truck or other means while it is rotating, it may move about the spherical bearing.

A ball ring 64 secured to the gear case 24 cooperates with a lip seal 66 to provide an encased housing for the drive and support.

To provide the necessary angularly downward force for holding the drum onto the part spherical bearing 50 there is a floating bearing means including an inner member 70 which may float radially and an outer member 72 and the shims or Belleville washers 74 between the outer space and a cover plate 76. That is, one side of spacer 70 is flat and is slidable on the adjoining flat surface of hub 52 in a plane normal to the axis of hub 52. The center of load of the drum support is at 78 and the cooperating surfaces between the spherical bearing parts 50 and 62 are on a curvature from a center at the center of load. Similarly, the mating surfaces between spacers 70 and 72 are on a radius with its center at the center of load. I

In operation the truck engine drives hydraulic pump 18 which supplies hydraulic fluid to motor 20 which activates the gear reduction unit 22 rotating shaft 24. The gear coupling including the external drive flange 46 rotates the drum through internal drive flange S6. The drum being inclined downwardly rests and supports on the part spherical bearing surface 50 through the cooperating mounting surface 62 with the center at the center of load. Due to the limberness or flexibility of the truck as it passes over bumps or the like, the axis of the drum 12 will not rigorously coincide with the axis of the drive shaft 12. The spherical bearing components 50 and 62 maintain the intersection of the axes of shaft 24 and drum 12 at the center of load 78 so that the single coupling provided by drive coupling members 46 and 56 allow for misalignment which is normally encountered in operation.

I claim:

1. In a truck-mixer having a concrete mixer drum which is rotatably supported on an inclined axis and is driven and rotatably supported at its lower closed end by a rotary drive and support shaft with means to allow for misalignment, the improvements comprising: a part spherical bearing between the drum and support shaft with the center of the bearing surfaces at the center of load, a gear coupling drive between the closed end of the drum and the drive shaft in a plane passing through the center of load, bearing means rotatably supporting the drive shaft including a main shaft support bearing closely adjacent the center of load so as to minimize the unsupported length of the drive shaft between the main shaft support bearing and the center of load.

2. A truck mixer as defined in claim 1 further comprising a floating hold-down bearing means between the upward end of the support shaft and the closed end of the drum.

3. A truck mixer as defined in claim 2 wherein the gear coupling drive includes an external drive flange splined to the drive shaft having teeth meshing with teeth on an internal drive flange attached to the drum, and wherein the main shaft support bearing is immediately adjacent the external drive flange 4. A truck mixer as in claim 2 wherein the hold-down bearing means comprises complementary spherical bearing members at the uppermost end of the support shaft, one of the members contacting a face of the drum hub, and a spacer means between the end of the shaft and the other member.

5. A truck mixer as in claim 4 wherein the spacer means are Belleville washers and the surfaces between the bearing members are spherical with the center of curvature at the center of load 

1. In a truck-mixer having a concrete mixer drum which is rotatably supported on an inclined axis and is driven and rotatably supported at its lower closed end by a rotary drive and support shaft with means to allow for misalignment, the improvements comprising: a paRt spherical bearing between the drum and support shaft with the center of the bearing surfaces at the center of load, a gear coupling drive between the closed end of the drum and the drive shaft in a plane passing through the center of load, bearing means rotatably supporting the drive shaft including a main shaft support bearing closely adjacent the center of load so as to minimize the unsupported length of the drive shaft between the main shaft support bearing and the center of load.
 2. A truck mixer as defined in claim 1 further comprising a floating hold-down bearing means between the upward end of the support shaft and the closed end of the drum.
 3. A truck mixer as defined in claim 2 wherein the gear coupling drive includes an external drive flange splined to the drive shaft having teeth meshing with teeth on an internal drive flange attached to the drum, and wherein the main shaft support bearing is immediately adjacent the external drive flange.
 4. A truck mixer as in claim 2 wherein the hold-down bearing means comprises complementary spherical bearing members at the uppermost end of the support shaft, one of the members contacting a face of the drum hub, and a spacer means between the end of the shaft and the other member.
 5. A truck mixer as in claim 4 wherein the spacer means are Belleville washers and the surfaces between the bearing members are spherical with the center of curvature at the center of load. 